Electric safety pilot



H. A. MANTZ ELECTRIC SAFETY PILOT Dec. 15, 1936.

Filed Oct. 1, 1954 Patented Dec. 15, 1936 UNITED STATES PATENT orrica ELECTRIC SAFETY PILOT Application October 1, 1934, Serial No. 748,891

3 Claim.

This invention relates to safety pilots, and is more particularly directed to safety pilots for use in domestic gas ranges, hot water heaters, 83 burners and the like.

' v In a preferred embodiment of the present inber disposed within the tip and responsive to the heat thereof for controlling a safety fuel supply valve disposed in the gas manifold. The

particular construction shown in the present in- 15 vention may be employed for either mechanical or electrical control of the safety valve.

The present invention has for its primary ,object the provision of a safety pilot which is incapable of becoming clogged by deposits of resiw dues or gums from the gaseous fuel; and which is extremely resistant to drafts or the like, whereby the heat of the pilot may be employed to secure positive control of a diaphragm or solenoid type of valve, or may be employed for a transmission of mechanical motion to a mechanical type of valve.

, A further object of the present invention is to provide a thermally responsive element which is enclosed within the pilot tip itself, andis therea fore subjected only to the heat of the pilot flame, being insulated and protected by the tip from the influences of outside temperatures.

A still further object of the present invention is to provide a thermally actuated mechanism 35 enclosed within the pilot tip and the lighter tube leading from the fuel supplyline, and which is capable of controlling a remotely disposed valve.

Another object of the present invention is the provision of a thermally responsive member in 40 the pilot tip which is capable of translating the temperature sensings of the mechanism to mechanical motion at a point removed from the tip without any moving structural elements therebetween.

A distinct advantage provided by the present invention is the provision of a simplified selfcontained safety pilot of compact design, having no intricate operating parts, and which is economical in cost and reliable in operation.

Other objects and advantages of the present invention will appear more fully from the following detailed description which, taken in connection with the accompanying drawing, will dis- 5 close to those skilled in the art the particular construction and operation of a preferred form of my invention.

In the drawing:

Figure 1 is a-diagrammatic plan view of a domestic type of gas range provided with the safety 5 pilot of the present invention;

Figure 2 is a vertical sectional view taken through the safety pilot shown in Figure l, illustrating in detail the construction thereof;

Figure 3 is an end elevational view of the safety pilot shown in Figure 2; and

Figure 4 is a detail diagrammaticview of a modified form of the invention.

Referring now in detail to the drawing, a fuel supply line is indicated generally at 5, and communicates with the fuel conduit 8 through the solenoid valve, or a diaphragm type of valve indicated diagrammatically at I.

The conduit 8 is adapted to conduct fuel from the supply line 5 to a gas manifold 8, which manifold is adapted to supply a plurality of burners 9 connected thereto through the valve iii.

A pilot hood is indicated generally at I2, and is provided with radially extending flash tubes i3 leading to the adjacent portions of the burners 9, whereby when fuel is supplied to one of the burners 9 the fuel issuing from the ports covered by the tubes ill will be conducted to the pilot flame within the hood I2, ignited by this flame, and flashed back to the burner to ignite the same. The pilot flame within the hood I2 is adapted to receive its fuel supply through the lighter tube It, connected to the manifold 8.

Referring now to Figure 2, the supply manifold t is connected, through the L connection it, to a body member Il having the chamber i8 therein receiving fuel from the manifold 8 through the connection iii. The lighter tube I4 is threaded into and communicates with the chamber it at one end, and at the opposite end is threaded into the elbow l9, which elbow is turned upwardly, and is recessed at its opposite end to receive the porous hollow ceramic tip 20.

This tip 20 is in the form of a cylindrical member having a rounded closed end, and being open at its opposite end, which communicates with the interior of the elbow l9. Suitable cementing means 22 is disposed around the outer surface of the tip 20 adjacent the end of the elbow IQ for 50 securing the tip in position with respect thereto. Interposed between the lower peripheral edge of the tip 20 and the shoulder formed in the elbow i9 is an annular supporting member 23, having. downturned tongues formed therein providing 55 oulb member tip 20.

a pleasure in uprightwiihin the sealed pressure contrac r decre bellows Illaougli which gas thereturn, sealed to the a second I ins memi to carry a n is supported neans or the iber 3 is terminals sting closure the chain erminal lugs 2;, the condom iii of a transe bellows connected ml of the ndlcated at :nually conno to prcthe the the dit is cenz a; 43 of the ll, the switch conductor 56' and from the solenoid. fiery of the transformer. nt that by moving the train the contact toren and the valve 1 will 'ion of the pilot lighter,

so about the outer surface ill by reason oi porous Jne heat oi this flame is transterio': of the tip, thereby die pressure bulb 25. The iiie about the suriace of this ension of the fluid therein, of the fluid is transmitted tube 2'! to the bellows 18, moving: the 1:. ing member 3 into contact across terminals ol and 38 to close a circuit for maintaining the valve member I open.

While the pilot burner is being ignited, that is, while the temperature of the pressure bulb 20 is still relatively cool, the manually operable switch 48 may be closed for opening the valve 1 in order to provide a proper fuel supply to the pilot burner. Upon release of the switch 48. the

crease in bulb res" and this through tie switch moves to its open position, and thereafter the operation of the valve 1 is controlled solely by means of bellows 28 which, in turn, is moved in accordance with the temperature sensings of the pressure responsive member 26.

The particular tip provided is capable of offering strong resistance to drafts, since the flame burns about the entire surface of the tip and therefore will tenaciously cling to the leeward side of the tip when a draft is blowing over the same. This particular type of tip will maintain a flame with a wind pressure of ten miles per hour. Further, the tip, because of its ceramic composition, is capable of producing a relatively high temperature within the interior thereof, which is desirable for effecting positive control of the bellows 28 through the pressure responsive member 26. At the same time, this high temperature within the tip prevents the depositing of any gums or residues from the gas within this chamber, and thereby prevents clogging of the pilot burner by such residues, as no metering valve is required in a pilot burner using this type of ceramic tip.

It will be noted that the entire control mechanism for the switch is disposed within the pilot tip and the lighter tube, with none of the parts beingexposed to the influence of outside temperatures, or subjected external mechanical injuries. Thus a compact and simplified. design is provided, and no moving parts need be provided between the pilot burner or tip 20 and the switch mechanism, inasmuch as the fluid pressure is transmitted therebetween to produce a translation of the heat the pilot tip into movement at a remotely disposed point. It is thus apparent that a remotely disposed valve, such as the valve 1 in the fuel supply line, can be controlled by the pilot; tip and switch structure shown.

In Figure 4, I have provided a similar construction, in which the incoming fuel supply manifold indicated at i; into a valve body 56 having the valve 5i therein, with a range manifold 55 or the extending outwardly from opposite sidesoi the valve body 66. The range manifolds 58 provide a fuel supply to the burners 9 and co :spond to the manifold I. The iuel supply line 55 corresponds to the line 5 of Figure 1.

The pilot lighter tube, indicated at i4", is fed from a passageway 59 drilled in the valve body 56 and communicating with the outlet chamber 80 oi. the valve body so that fuel supply to the outlet chamber will pass through the passageway I! and to the pilot tip.

An expansible bellows 52, corresponding to the bellows 28 of Figure 2, mechanically connected to the valve stem 83, whereby upon expension or contraction of the bellows l2 '1 response to changing temperature conditions at the pilot tip, the valve stem 53 is reciprocated to open or close the valve member 51, thus controlling the now of fuel from the fuel supply line I to the manifold II,

It will be noted, in this modification, that the temperature sensed within the pilot tip will be translated into mechanical motion of the valve stem 83 by means 01' the pressure connection through the bellows 82, whereas in the previous embodiment an electrical contact was made or broken in order to control the operation of a remotely disposed valve.

It is to be understood that any desired type of switch arrangement may be provided in place of the bridging contact I and contact terminals pl li y Someofthelowergradeeofgaseousfuelnowprovided contain a relatively large percentage of what is termed "vapor-phase gum or residues, which deposit upon any cooled surfaces forming a restriction to the flow of fuel. BY the provision of thenovel type of pilot tip, together with the lighter tube arrangement which I have disclosed, there is no restriction placed in the path of the flow of fuel from the manifold 8 to thepilot tip, except the port holes 24 through the supporting spider 23. However, the temperature adjacent this zone ismaintained relatively high, due to the character of the tip, its extent down into position adjacent the epider, and the flame burning thereon, and consequently there will be no residues or gum deposited about this surface. This is distinctly advantageous, in that there is no danger of the gas eway becoming clogged or otherwise failing to function positively, and at the same time, there is no necessity for frequent cleaning or inspection service,

Having described my invention in accordance with the patent statutes, I do not intend to be limited to the specific embodiments which have been illustrated in connection with the description of the inventim, but'only insofar as deflned by the scope and spirit of the appended claims. I

I claim:

1.-In a pilot burner construction, a lighted tube, a housing at one end of said tube connected to a fuel supply manifold, a terminal plate carried by said housing, switch contacts therein, a closed chamber in saidzhousing having a bellows secured to one wall thereof, contact bri sins means carried by said bellows and positioned to engage said contacts upon movement of said bellows, an elbow at the opposite end of said tube, a cup-shaped hollow porous pilot tip supported on said elbow and receiving fuel from said manifold, a spider interposed betweentheopenendofsaidtipandsaidelbow,

a fluid fllled thermostatic bulb supported on said spider and extending into said tip, and means providing communication between the interior of said bellows and said bulb and disposed within said lighter tube whereby expansion of the fluid within said bulb in response to temperatures at said pilot tip will produce mechanical movement of said bellows.

2. In a pilot burner construction, a lighter tube, a housing at one end of said tube provided with means for connection to a source of gas, a'terminal plate closing said housing and having switch contacts disposed within said housing, a wall in said housing forming with said terminal plate a closed chamber therein, a bellows in said chamber, contact bridging means carried by said bellows and positioned to engage said contacts upon movement of said bellows, a cup-shaped pilot tip at the opposite end of said tube communicating with the interior thereof, a fluid-filled thermostatic bulb within said tip, and means disposed entirely within said lighter tube and providing communication between said bulb and said bellows whereby expansion of the fluid within said bulb in response to temperatures at said tip will produce mechanical movement of said bellows.

3. A safety pilot including a lighter tube, an elbow at one end of said tube having a verticallv directed opening, a cup-shaped pilot tip having its open end secured in said opening, a housing at the opposite end of said tube adapted for connection to a fuel supply manifold, a sup.- porting spider engaged between the open end of said tip and said elbow, thermally responsive presume-developing means supported by said spider entirely within said tip, contacts carried by said housing, a pressure-responsive bellows means in said housing connected through said tube to said pressure-developing means, and a contact bridging member carried by said pressure responsible and movable thereby upon increases in p w at-said pressure-developing means for eng sins said contact.

, HAROLD A. MANTZ. 

